Engine problems continue

[cstello]

Ok, I have done everything I think possible to try to diagnose my issue. My boat has a monsoon with the chevy 350. The motor will only get up to 3900-4000 RPMs and about 35 MPH. I think it is the computer putting the motor in a safe mode but I don't know why. I used a code reader and only one code came up, 14 which is a coolant temp sensor. I cleared the code and it didn't come back. Any suggestions?

[skier92]

35 mph sound fast for safe mode, but, did you notice any overheating at any time prior to problem? Assuming it was an overheating problem, did you check both the raw water pump impeller and the trans oil cooler. (taking both water hoses off to check is the best way, as you can see if any small debris, that might otherwise be missed by only removing bottom hose and checking by feel) Check that there are no obstructions in water hose and any devices between water pickup and water pump. Can anyone confirm that a code reader can be used to erase a code that puts the system in safe mode?

Edited May 3, 2009 by skier92

[rinconking]

have you changed your fuel filter lately? is it possible that you have bad gas, or water in the gastank? try changing the coolant temp sensor(should be cheap from napa).

[RTS]

Your Monsoon has a 'phased warm-up' to ensure the engine is warm before full RPM is possible.

The RPM limit is 4200RPM until the engine is 140 degrees plus 10 seconds. If your temp sensor is bad, and makes the ECM think the engine is not over 140 degrees, that may be your problem, especially since you say the ECM had a code for a faulty sensor.

Sounds like it is definitely worth a try to replace the temp sensor.

BTW, you should only be able to get 3000 RPM until the enigine is 103 dgrees plus 10 seconds.

Hope this helps.

[cstello]

35 mph sound fast for safe mode, but, did you notice any overheating at any time prior to problem? Assuming it was an overheating problem, did you check both the raw water pump impeller and the trans oil cooler. (taking both water hoses off to check is the best way, as you can see if any small debris, that might otherwise be missed by only removing bottom hose and checking by feel) Check that there are no obstructions in water hose and any devices between water pickup and water pump. Can anyone confirm that a code reader can be used to erase a code that puts the system in safe mode?

I did erase the code that was being sent. I ran it and checked it again and the code wasn't there again. Will erasing the code change the way the engine runs (take it out of safe mode)? Also, I just changed both my fuel filters. What about cap and rotor? Will they cause an issue like this?

[JUST-IN-TIME]

35 mph sound fast for safe mode, but, did you notice any overheating at any time prior to problem? Assuming it was an overheating problem, did you check both the raw water pump impeller and the trans oil cooler. (taking both water hoses off to check is the best way, as you can see if any small debris, that might otherwise be missed by only removing bottom hose and checking by feel) Check that there are no obstructions in water hose and any devices between water pickup and water pump. Can anyone confirm that a code reader can be used to erase a code that puts the system in safe mode?

I did erase the code that was being sent. I ran it and checked it again and the code wasn't there again. Will erasing the code change the way the engine runs (take it out of safe mode)? Also, I just changed both my fuel filters. What about cap and rotor? Will they cause an issue like this?

cap and rotor would cause a misfire

never trust a code reader, they just tell you what might be wrong

no you need to test if the temp sensor is getting its 5v reference and a good ground

if you have not run he boat yet, run it and get back to us